metasploit-framework/external/source/msfJavaToolkit/javaCompile/CreateJarFile.java

// Source: http://www.java2s.com/Code/Java/File-Input-Output/CreateJarfile.htm

package javaCompile;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;
import java.util.jar.Manifest;

public class CreateJarFile {
	public static int BUFFER_SIZE = 10240;
	public static void createJarArchive(File archiveFile, File[] tobeJared) {
		try {
			byte buffer[] = new byte[BUFFER_SIZE];
			// Open archive file
			FileOutputStream stream = new FileOutputStream(archiveFile);
			JarOutputStream out = new JarOutputStream(stream, new Manifest());

			for (int i = 0; i < tobeJared.length; i++) {
				if (tobeJared[i] == null || !tobeJared[i].exists()
						|| tobeJared[i].isDirectory())
					continue; // Just in case...
				//System.out.println("Adding " + tobeJared[i].getName());

				// Add archive entry
				JarEntry jarAdd = new JarEntry(tobeJared[i].getName());
				jarAdd.setTime(tobeJared[i].lastModified());
				out.putNextEntry(jarAdd);

				// Write file to archive
				FileInputStream in = new FileInputStream(tobeJared[i]);
				while (true) {
					int nRead = in.read(buffer, 0, buffer.length);
					if (nRead <= 0)
						break;
					out.write(buffer, 0, nRead);
				}
				in.close();
			}

			out.close();
			stream.close();
			//System.out.println("Adding completed OK");
		} catch (Exception ex) {
			ex.printStackTrace();
			System.out.println("Error: " + ex.getMessage());
		}
	}
}